CNSC-94. A NOVEL CASE OF ARID1A MUTATION IN PEDIATRIC CHOROID PLEXUS TUMOR

Abstract BACKGROUND Choroid plexus papillomas (CPPs) and choroid plexus carcinomas (CPCs) represent the two most common subtypes of choroid plexus tumors. Various genetic alterations have been discovered in their molecular characterization. We discuss a case of a 9-year-old male with a recurrent atypical CPP (WHO Grade 2) who underwent three surgeries and highlight the complexities of management. Methods included molecular analysis of the tumor, revealing a novel ARID1 mutation. The tumor was treated as CPC due to aggressive behavior and the presence of this mutation. The patient is currently receiving chemotherapy with carboplatin, etoposide, and vincristine. Radiation oncology has been involved. Results showed that the tumor recurred despite initial gross resection, requiring repeat surgeries to manage the disease. A multidisciplinary approach was adopted due to the failure of aggressive surgical management. The patient was scheduled for radiotherapy involving CT simulation followed by daily radiotherapy for 30 fractions. CONCLUSIONS This case emphasizes the importance of molecular characterization in pediatric choroid plexus tumors and the need for further research on ARID1 mutations in these tumors. ARID1 mutations have been recognized in various adult malignancies like atypical teratoid and rhabdoid tumors, but their presence in pediatric CPTs has not been previously reported. The presence of an ARID1 mutation might indicate a more aggressive tumor course and necessitate adopting a multidisciplinary approach. Our case report contributes to the growing body of literature on the management of these complex tumors. Choroid plexus tumors (CPTs) are rare, and there is a lack of established treatment protocols for recurrent CPTs with ARID1 mutations. Ongoing follow-up will be necessary to determine the long-term efficacy of this treatment approach.